Hydraulic let-off



De@ l5, 1942- A. J. HERARD, JR 2,305,420

HYDRAULIC LET-OFF Filed oct. 13, 1941 2 sheets-sheet 1 .gli

lNvcN-ron ARCHIBALD CI'. HER/nomi ATTORNEY Dec. 15, 1942.

A. J. HERARD, JR

HYDRAULIC LET-OFF Filed Oct. 15, 1941 2 Sheets-Sheet 2 ATTORNEY PatentedDec. 15, 1,942

Archibald J. Hei-ard, Jr.,

signor to Crompton & Knowles Loom.

Worcester, Mass., as-

Works.

Worcester, Mass., a corporation of Massachusetts Application october 13,1941seria1No. 414,729?

' V10` Claims. (Cl.

This invention relates to let-olf mechanisms for. looms and it isthegeneralobject of the invention to provide a let-off controlledhydraulically by tension of the warp threads.

In certain types of let-off mechanisms itis customary to employ a whiproll which is moved forwardly by the tension ofv the warp during theweaving operation and while the warp beam is held stationary. When thewhip. roll reaches a given forward position mechanism is-operated torelease the warp -beam so that-it can be turned by theV warp to reducetension and permit the whip roll to move rearwardly under the action ofa weight or spring; When the whip roll reaches a critical rearwardposition the warp beam is again locked, and the alternate locking andunlocking of the beam by back and forth motion of the whip roll goes onthroughout the weaving operation to supply the warp under proper tensionas needed.v

It is an important objectof my present invention to provide a hydraulicsystem for controlling the warp beamtogether with means for acting onthe system by mechanism dependent for'its operation upon a part, suchasa whip roll, the position of which is changed by the warp. Myinvention contemplates` the use of brake shoes operated by a hydraulicunit connected, to ahydraulic cylinder the plunger of which.iscontrolled by the part to holdand release the beam 1 alternatelyduring loom operation. Thesystem normally tends to cause the brake shoesto hold the warp beam stationary, and as thel whip.- roll movesforwardly the pressure within the system is gradually reduced until thebrake shoes slacken` enough` to permit the Warp beam to turn. During theconsequentslackening of the warp ,threadsthe whip roll moves rearwardlyunder action ofA the weight and acts .on' the cylinder plunger to returnthe shoes `to locking position. In the description to follow Ihaveillustrated a single system appliedto but one end ofthe loom, butl".am not limited, to such an application, as itis obvoius that themechanism canvbe duplicated at the opposite end.

With these and other objects in view which will appear as thedescription proceeds, my invention resides in the combination and`arrangement of partsl hereinafter described and set forth.

In the accompanying drawings, wherein a convenient embodiment of myinventionis set forth, Y Fig. 1 is a rear elevation of-one end of a loomhaving my invention applied thereto,

Fig. 2 is a plan viewv taken in the direction of yarrow-1,21ig. 1 and;`showing the-,hydraulic sys'f tem under control of both ends of the whiproll, l

@ liig.` 9 is a vertical section through the brake operating hydraulicunit shown in elevation in Fig. 6.

i Referring particularly, to Figs. 1, 2 and 3,k I have shown a loomframeI', warp beam Il andv whip roll I2; of the usual construction. A bracketI3 securedto the loom frame extends rearwardly and: has pivoted theretoasn at I4 an upwardly extending yarm I5 on which the adjacent end -ofthewhip roll is journaled as at I6. The warp W fromfthe warp beam is ledupwardly 4and over thewhp roll and then forwardly to the pointof;weaving.

A lever swinging in a vertical plane is pivoted as at 2| on the bracketI3 and has-a horizontal arm to support a weight rod 22` the lower end ofwhich carries weights 23. As vshownparticnlarly in Fig.12 acontrollever25 swinging in afhorizontal lplane is pivoted, as at A26 'to the bracketand has a lateral arm 21 to engage the front edge ofthe adjacent arm I5.Lever 25 also has a forwardly extending arm ZBYpivoted as atf'29 to alink 30 which in turn is pivoted to a second linkv 3l the right end ofwhich is shown inv Fig. 1 as pivoted at 32 to a part of lever 2i) abovethe pivot 2I. A rod 33 connected to link 30 in `the' present instance isshown in Fig. 2 as extending across the loom to be connected to a secondcontrol: lever .similar to lever 25 to engage an, arm 36 similarv tovarmI5 onwhich y the leftend ofthewhip roll is journaled.`

YIn the mechanism thus far described, andassuming for the momentthat thewarp kbeam is stationary, the whip roll I2 will moveforwardly to swingthe arms I5 and 36 toward-thefront of the loom and effect alefthandangular motion of levers 25 and 35 asviewedin Fig. 2. The attendantmotion of arm-'28 to the leftlifts lever 2U against the action of theweights 23 which serve to tension the warp threads W. When the warplbeam is free to turn and thus reduce the tension in the warp threadstheweights 23 fall and act through lever 20 and links 30 andl 3l to turnlever 25 in a right hand. direction vas viewed inFig, 2 to movethe armI5 andfwhip 2,184,059 to which reference may be had for a.

further understanding of the structures already set forth.

The warp beam which I employ has secured thereto a shell to havefrictional contact with. brake shoes mounted on a xed support which alsosupports the hydraulic brake shoe controlling unit as shown moreparticularly in Figs. 6

and 9. Secured to and extending rearwardly from the loom frame is abracket 40 provided with a bearing 4| through which extends the rightlend of the warp beam gudgeon or shaft 42`as seen in Fig. 7. A disk 43bolted as atv 44 to bracket 40 supports studs 45 connected by a link 46,as indicated in Figs. 6 and '7. As shown in Fig.V 6 theV right and leftstuds 45 which pass through link 46'have pivoted thereon brake shoes 41and 48, respectively, which extend upwardly to a hydraulic brake`operating unit 49. The latter is held as at 58 to the disk 43, seeFigs. 6 and 7, and is connected to a hydraulic tube 5|. 'Ihe brake shoesare therefore supported on fixed structure as is also the unit 49 andthese parts are held against rotation around shaft 42v as will beapparent in Figs. 3 and 7.

The barrel of the warp beam is fastened to shaft 42 and has securedthereto a head 56 to lwhich is secured a drum 51.v A hub 58keyed toshaft 42 lies to the right of web 59 of the drum, and the hub, web andhead are bolted together as at 60 to turn with the warp beam. Rods 6|located in grooves 62 extending longitudinally along the periphery ofthe barrel 55 are secured to the head 58, and act with shaft 42 to causethe drum to rotate with the barrel 55. The drum is formed with aninternal cylindrical surface 63 positioned for engagement with `theexternal surfaces of the' shoes 41 and 48. `rI he drum rotates with thebarrel to feed n.warp and can either slide along the brake shoes if thelatter are spaced from surface 63 as shown in Fig. 6, orbe' held by theshoes if they are forced apart and against surface 63 by the "unit 49.In -the latter instance the beam Awill be locked or -held in stationaryposition because of the support afforded the brake shoes by the bracket40.

The unit 49 which issecured to the disk 43 and shown in Fig. A9comprises a cylinder 65 having an Vinlet port-B6 intermediate the endsthereof on opposite sides of which are located front and back pistons 81and 68, respectively. Rubber cupsY 69 Contact the inter-nal bores of thecylinder and each piston is provided with a pressure plug 10 forengagement with the corresponding shoes 41 and 48; The ends of thecylinder may be closed'byrubber boots 1|, and a light compression spring12 engages the cups 69 to hold them against their respective pistons.The fluid withinthe cylinder is confined between the cups and whensubjected to increased pressure tends to move the pistons apart to forcethe brakeshoes against the cylindrical surface 63 of the drum 51. Whenpressure wlthin the cylinder 65 falls the pressure exerted by thepistons slackens and in order to insure release of the shoes from thebraking surface 63 I employ a tension spring 13 between the shoes 41 and48 tending to draw the latter away from surface 83, as shown in Fig. 6.

The pressure of fluid in the member 49 is controlled through tube 5|which leads to a cylinder mounted in the present instance in fixedposition and having a plunger the position of which can be changed tovary the fluid pressure within the system. As shown in Figs. 3 and 8 thebracket I3 has secured thereto a small stand 15 on the upper end 18 ofwhich is mounted the pressure unit 11. The latter has a uid reservoir 18on the upper part thereof communicating by means of aport 19 with acylinder bore 80. A piston 82 slides in the bore 80 and is movable alongthe latter by a piston rod 83 the left end of which as seen in Fig. 2 islocated for engagement with the arm 28. A by-pass port 85 leads from thereservoir to the bore 88 and a rubber cup 86 is normally located betweenthe intake and by-pass ports, lbeing heldagainstthe piston 82 by a,compression spring 81. A 'stop 88 limits motion of the piston to theleft as viewed in Fig. 8 and serves to locate the cup,86 with respect tothe ports.

The right end of spring 81 bears against a disklike structure 98 limitedas to right hand motion by the end of the bore and having mountedtherein a valve 9| which when open by fluid pressure incident to motionof the piston .82 to the right, Fig. 8, leads to the tting 92 the boreof which communicates with the hydraulic'tube 5|.

The relationship ofthe unit 49, tube 5| 'and cylinder 11 is such thatwhenv the rod 33 moves 'to the right as viewed in Figs. v2 .and A8 fluidwithin that part of the bore lying to the right of the by-pass port willbe placedunder pressure land this pressure will be communicated throughthe tube 5| to the pistons 61 and 8.8. When the force acting on rod 33is released or reduced, the spring 81 moves the piston to the left toeffect a reduction of uid pressure withinV the system .and spring 13draws the pistons 81 and 68 toward each other.

In operation, the weight 23will actas already described Vto hold thearm-28 in a right hand position, Fig. 2, when the whip roll is in itsrearmost position, thus causing arm 28 to exert a force on piston rod 83to the right as viewed in Figs. 2 and 8 to produce a relatively highlevel of fluid pressure within the system and cause the brake shoes 61and 88 to move against the drum 51 and hold the beam stationary. As warpis consumed the whip roll lwill move forwardly, thereby moving the arm28 to the left or in-a direction away from the piston rod 83, whereuponthe spring .81 will act to reduce the fluid pressure within the systemuntil a, level is reached which permits the beam to.turn with respect tothe brake shoes.l The tension .spring 13 assists ina vquick releaseofthe brake shoes but is notV essential. When Vthe beam is vreleasedthetension in the warp rotates the beam to feed warp forwardly with aresultant drop in warp tension which permits the weight 23 to move thewhip roll rearwardly until arm y28 again moves piston rod 83 to theright to reestablishfbeam holdingpressures within the hydraulic system.l

'Ihe back and Vforth reciprocation of the whip roll goes on throughoutthe Weaving operation, the whip roll moving forwardly to a given pointin its Acycle at which fluid pressure dropsfsuflicientlyrto releasethebeam, whereupon the whip roll is returned by the weight to asecondtgiven point in its rearward travel at which holding pressures areagain established. The drum surface 63 slides smoothly over the shoes 41and 48 to avoid abrupt 'movements of the warp beam and in this way' aneven feeding action of the beam is attained.

From the foregoing it will be seen that I have provided a simpleandefficient means for regulating the locking and releasing of the Warpbeam by means of a hydraulic system the fluid pressure of which risesand falls constantly during loom operation to lock and release the warpbeam alternately. It will further be seen that the piston rod 83 isacted upon by means, such as the whip roll and arm 28, responsive tovariations in tension in the warp and that increasing tension in theWarp operatesV through the hydraulic system to unlock thebeam. It willalso be seen that the weight 23 serves not only to move the whip rollrearwardly when the warp is slackened but also supplies theforce neededto establish beam holding pressures within the hydraulic system.

The brake unit Q9, tube and pressure unit 11 as shown in Figs. 8 and 9of themselves form no part of my prsent invention and may be of anyapproved form.` For a further understanding of these parts reference maybe had to printed matter relating to hydraulic brake systems, such forinstance as subject #2062 and 2140 shown in the catalogue of November13, 1938,y of the Ford Motor Company. y

Having thus described my invention it will be seen that changes andmodifications may be made therein by those skilled in the art withoutdeparting from the spirit and scope of the invention and I do notwish'to be limited to the details herein disclosed. but what I claim is:

1. In a warp let-off mechanism vfor a loom having a rotatablevwarp beam,brake means for the beam movable.' either to holding position to preventrotation of the beam or to releasing position to permit rotation of thebeam, a hydraulic system connected to the brake means, mechanism actingnormally on the systemito cause the latter to move the brake means tobeam holding position, and other means to transmit an opposing force tothe mechanism derived from the warp asthe tension of the latterincreases during the weaving operation while the beam is prevented fromrotating and cause the mechanism to effect a reduction of uid pressurewithin' the system to a level insuihcient to cause the brake means tohold the beam from rotation.

2. In a warp let-off mechanism for a loom having a rotatable warp beam,brake means for the beam, a hydraulic system connected to the brakemeans to control the amount of braking force exerted by said brake meanson the warp beam, controller means for the hydraulic system, meansoperated by a force derived from the warp as the tension in the latterincreases during the weaving operation when the warp beam is preventedfrom the rotating to cause -the controller means to effect a reductionof uid pressure within the hydraulic system to a level which permits thewarp beam to move relatively to the brake means, and other meansoperative due to slackening of the warp tension incident to rotation ofthe warp beam to cause the controller means to establish fluid pressurewithin the system sufficiently high to cause the brake means to preventrotation of the warp beam.

3. In a warp let-off mechanism for a loom having a rotatable warp beam,means moved from holding to releasing position by a force derived fromthe warp as the tension thereof increases during weaving, providec'irotation'of the beam is prevented, brake mechanismv to'control rotationof the beam, a hydraulic system controlling the brake mechanism andvunder control of said means, return mechanism for the means to move thelatter from releasing to holding position When tension in the warp isreduced, the means when in holding position maintainingsuicient'pressure within said system to cause th'e brake mechanism toprevent rotation of said beam, said means when moving to releasingposition reducing? the pressure within the system to a levelinsufficient to cause the brake mechanism to prevent rotation of thebeam, whereupon the warp due to the tensionv thereof causes rotation ofthe beam to reduce the warp tension and the return mechanism moves themeans to holding position to reestablish suiiicient pressure in thesystem to prevent further rotation of the beam.

4. In a warp let-off mechanism for a loom having a rotatable warp beam,brake means for the beam movable either to beam holding or releasingposition, a hydraulic system connected to and controlling the brakemeans, a whip roll movable forwardly to a given position during theweaving operationv by a force derived from the warp when the warp beamis held against rotation, means tending normally to move the whip rollrearwardly toca second given position, and mechanism `to vary thefluidpressure within the system, said mechanism being caused by a forcederived from the whiproll when the latter moves forwardly to said firstgiven position to produce a pressure within the system insufficient tocause the brake means to hold the warp beam, and said mechanismeffective when the whip roll moves rearwardly to said second givenposition to produce sufficient pressure within the system to cause thebrake means to hold the warp beam against rotation.

5. In a warp let-off mechanism for a loom having a rotatable warp beamand a whip roll movable forwardly by the Warp during'the weavingoperation when the beam is prevented from rotating, the loom havingreturn means to move the whip roll rearwardly due to lessening of thewarp tension when the beam rotates to feed warp, brake means for thebeam movable toholding position tov prevent rotation of the beam,release means to move the brake means to releasing positionto permitrotation of the beam by the Warp, a member moved by the whip roll fromholding to releasing position when the whip roll moves forwardly, saidreturn means to move the member from releasing to holding position whenthe whip roll moves rearwardly, and ahydraulic system .connectedv tothev bra-ke means and` controlled by the member to have the pres-- suretherein increased to move the brake means to holding position whenthe'member moves to holding position, and have the pressure thereinreduced when the memberkmoves to releasing position, whereupon therelease means moves the brake means to releasing position.

6. In a warp let-off mechanism for a loom hav-- ing a rotatable warpbeam and a whip roll movable forwardly by the warp during the weavingoperation when the beam is prevented from rotating, the loom havingreturn means to move the Whip roll rearwardly due to lessening of thewarp tension when the beam rotates to feed warp, brake means for thebeam movable to holding position to prevent rotation of the beam,release means to move the brake means to releasing position to permitrotation of the beam by the warp, and a hydraulic system connected tothe brake means and controlled by the whip roll and said return means,the whip roll when moving forwardly operative to decrease the pressurewithin said system to permit the release means to move the brake meansto releasing position, and said return means operative when the whiproll moves rearwardly to increase the pressure in said system tooverpower said release means and move the brake means to holdingposition.

7. In a warp let-off mechanism for a loom having 'a rotatable warp beam,a whip roll for the warp movable backwardly and forwardly, meansincluding a weighted lever tending normally to move the whip rollrearwardly, the warp due to increase in tension therein during theWeaving operation moving the whip roll forwardly against the action ofthe weighted lever when the warp beam is held against rotation, brakemeans for the warp beam movable to holding and releasing positions withrespect to the beam, a hydraulically operated unit for the brake means,a hydraulic cylinder having a plunger in position for operation by saidweighted lever, and tubular means connecting the unit and cylinder, saidunit, cylinder and tubular means constituting a hydraulic system, thelever when moving in a direction to move'the whip roll rearwardlyoperating the plunger to increase the fluid pressure within the systemand cause the unit to move the brake means to holding position withrespect to the beam, and said Weighted lever being moved in a directionaway from the plunger by forward motion of the whip roll reducing thefluid pressure within the system, whereupon the beam rotates withrespect to the brake means due to tension in the warp and said weightedlever moves the weighted lever rearwardly and causes the plunger tocreate suficient fluid pressure within the system to move the brakemeans toA beam holding position. A

8. In a warp let-off mechanism for a loorn hav- Whip roll forwardlyduring the weaving operation when the warp beam is prevented fromrotating, a lever having two arms one of which is operatively related tothe whip roll and movable therewith, a Weight connected to the secondarm ofthe lever, said weight tending normally to move the first arm in adirection to cause rearward motion of the'whip roll, brake means for thewarp beam movable to holding and releasing positions relatively to thebeam, vand a hydraulic system between said lever andthe brake meansincluding a unit to control the brake means, said system including acylinder having a plunger to be moved by the weight acting on the leverin a direction to lincrease the'uidpressure withinthe system-when thefirst named arm moves in the direction corresponding to rearward motionlof the whip roll to cause the-unit to move the brake means to beamholding position, movement of the first named arm in a directioncorresponding tov forward motion of `the whip roll moving the lever in adirection away from the plunger, whereuponl fluid pressure within thesystem 4is decreased to vpermit turning of the beam relatively to thebrake means, the weight being effective through the lever to movetheWhip roll rearwardlyand reestablish sufcient fluid pressure within thesystem tocause the brake means to prevent 'rotationof the warp beam. n.

9. In a Warp let-off` mechanism for amloom having a rotatable warp beam,brake means for the beam, a'hydraulic system connected vto the brakemeansto control the amount of braking force exerted therebyon the warplbeam, a whip roll moved forwardly by the warp during the weavingvoperation when the warp beam is prevented from turning,weighted meanstendingnormally to move the whip roll rearwardly, V'a controller yforthe system to determine the fluid pressure with-r in said system,controller actuator means by' which the whip roll when moving forwardlycauses the controller to reduce the lluid pressure within the system toa point which will permit the warp beam to turn with respect to thebrake means, and the weighted means effective' during rearward motion ofthe whipwroll. to move the. actuator means to cause the 'controller to-in-I crease the'fluid pressure of the system to a point whichv willcause the brake means to preventv rotation of the Warp beam.

l0. In a warp let-off mechanism for a loom having a rotatable warp beam,brake means'for the beam, a hydraulic system connected to the brakemeans to control the amount of braking force exerted by said brakemeansv on the Warp. beam, a controller for the hydraulic system movablein one direction toA decrease and in the 0p'- posite direction'toincrease the fluid pressure within said system, controller actuatormeans vto cause the whip roll when A,moving forwardly. to

move said controller in said 'onedirec'tiorr means to move the Whiproll. rearwardly a'n'dfmoveA the actuator means to cause movement ofthecontrolle'r in said opposite direction, the increase in fluidpressure within the system being sufficient crease. in pressurewithin'the' fluid system reach.- ing a level insufficient to enable th'ebrake means to prevent beam rotation when'the whip roll reaches a `givenposition in its forward motion.

